Rapid determination of postmortal changes in the protein profile of common carp (Cyprinus carpio) fillet powered by MALDI-TOF—the effect of storage temperature and time

Common carp (Cyprinus carpio) is one of central European aquaculture’s most reared freshwater fish. Its freshness fundamentally affects meat quality, given by the storage temperature and elapsed time between slaughtering and further processing. This study introduces a rapid and straightforward protocol using matrix-assisted laser desorption ionization time of fly mass spectrometry to investigate postmortem changes in the protein profile of carp filets stored in different temperatures (0—ice, 4—fridge, and 8 °C—shop shelf) during 120 h of storage. Lactate, adenosine triphosphate, and its derivates were determined to underline freshness evaluation. Three mass spectral clusters (proteins possessing similar mass values) with different occurrence behavior were determined based on multivariate statistical analysis. The first spectral cluster was absent in carp filets stored at 0 °C. The second cluster occurred in all temperatures, and the third was present only at 0 °C for the whole 120 h of the experiment while disappearing in other temperatures. Based on the presented protocol and the occurrence of particular spectral clusters, the freshness of C. caprio filets and their storage history could be considered.